Nitrophenylhydrazine compounds

ABSTRACT

N-Amino substituted aniline and 1,3-phenylenediamine compounds having 1 or 2 nitro groups on the aromatic ring. The compounds are useful as herbicides and as intermediates for preparing herbicides.

This is a division of application Ser. No. 529,655 filed Dec. 4, 1974and now abandoned.

This invention relates to novel nitrophenylhydrazine compounds and theiruse as chemical intermediates and as herbicides. There is provided bythis invention a class of N-amino substituted aniline and1,3-phenylenediamine compounds having 1 or 2 nitro substituents and haloand trifluoromethyl substituents on the aromatic ring.

The novel compounds of this invention can be defined by the formula##STR1## wherein X is selected from hydrogen and nitro, Y is selectedfrom halo, especially bromo and chloro, lower alkoxy, amino, alkylamino,dialkylamino, and ##STR2## Z is selected from halo, especially bromo andchloro, and trifluoromethyl, R₁ is lower alkyl, R₂ and R₃ are eachselected from hydrogen and lower alkyl, and in which R₁ -R₂ takentogether may represent an alkylene, alkyleneimino, or alkyleneoxylinkage having two to about six carbon atoms in the chain.

The compounds can be named as N-amino substituted aniline orphenylenediamine compounds or as nitrophenylhydrazine compounds. Theyare crystalline solids or high boiling liquids and are generallymoderately soluble in organic solvents such as ethanol, acetone, etherand benzene.

Preferably, the alkyl groups represented by R₁, R₂ and R₃ as definedabove and the alkyl substituents on the amino groups which can berepresented by Y have up to about 6 carbon atoms, including the cyclicanalogues thereof. Representative alkyl groups are methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, n-pentyl, sec-pentyl, n-hexyl,cyclohexyl, cyclopropyl, cyclobutyl, cyclopropylmethyl,cyclobutylmethyl, cyclopropylethyl, and the like.

Furthermore, R₁ -R₂ taken together can represent a fragment of a ring ofwhich the amino nitrogen is a part thereof, such as illustrated by thestructure ##STR3## in which Z is an alkylene group having from about 2to 6 carbon atoms in the chain, and optionally other atoms such asoxygen and nitrogen. Such linkages include the dimethylene,trimethylene, tetramethylene, diethyleneoxy, diethyleneimino,pentamethylene, and hexamethylene groups.

Typical lower alkoxy groups which can be represented by Y in the aboveformula include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy,hexyloxy, and the like.

When Y in the above formula represents halo, such as bromo or chloro,the compounds are useful as intermediates for preparing herbicidalcompounds in which Y represents lower alkylamino, alkoxy, amino, oralkylhydrazino groups. Such 3-halophenylhydrazine compounds can beprepared by reaction of the corresponding 1,3-dihalobenzene derivativeand a hydrazine compound according to the following equation: ##STR4##in which Hal is bromo or chloro and X, Z, R₁, R₂, and R₃ have thesignificance previously assigned. The reaction takes place at from aboutroom temperature to about 100° C., preferably in the presence of ahydrocarbon solvent. Since hydrogen bromide or chloride is formed as aby-product, an excess, i.e. two moles of hydrazine compound can becombined with each mole of dihalobenzene derivative. Hydrazinehydrohalide is therefore formed as a crystalline by-product in thereaction and can readily be removed by filtration or washing with water.Alternatively, other acid-consuming reagents such as tertiary amines canbe employed to neutralize the by-product hydrogen halide.

The 2,4-dihalonitrobenzotrifluoride starting materials are readilyprepared by nitration of 2,4-dihalobenzotrifluorides according to knownprocedures.

The following examples describe preparation of representative compoundsof this invention, but it is to be understood that the invention is notto be limited to the specific examples given.

EXAMPLE IN-(dimethylamino)-3-chloro-2,6-dinitro-4-trifluoromethylaniline

To 20.0 g. (0.065 mole) of 2,4-dichloro-3,5-dinitrobenzotrifluoride and300 ml. of cyclohexane in a 500 ml. roundbottom flask equipped with astirrer and dropping funnel was added 7.86 g. (0.13 mole) of1,1-dimethylhydrazine at ambient temperature. The addition was drop-wiseover a period of about 20 minutes. Stirring was continued for 22 hoursat room temperature. The resultant mixture was filtered and theinsoluble solid then stirred with 300 ml. of water for one hour todissolve the hydrazine hydrochloride. The insoluble product was isolatedby filtration and washed with water. Recrystallization from 95% ethanolgave 18.3 g. (85%) of the desired product as a yellow solid, m.p.130°-131° C.

EXAMPLE II 1,1-dimethyl-2-(3,4-dichloro-6-nitrophenyl)hydrazine

Reaction of 1,2,4-trichloro-5-nitrobenzene with 1,1-dimethylhydrazine asdescribed in Example I gave the desired product, m.p. 138°-143° C.

EXAMPLE IIIN-(methylamino)-3-chloro-2,6-dinitro-4-trifluoromethylaniline

The product was obtained by reacting2,4-dichloro-3,5-dinitrobenzotrifluoride with methylhydrazine and foundto melt at 136°-137° C. Other compounds which can be prepared by theabove-described procedures include:

N-pentamethyleneimino-5-chloro-2-nitro-4-trifluoromethylaniline, m.p.110.5°-112° C.

N-morpholino-5-chloro-2-nitro-4-trifluoromethylaniline, m.p. 122°-123.5°C.

N-pentamethyleneimino-3-chloro-2,6-dinitro-4-trifluoromethylaniline,m.p. 124°-127° C.

N-methyl-N-pentamethyleneimino-3-chloro-2,6-dinitro-4-trifluoromethylaniline;oil

N-(dimethylamino)-3,4-dibromo-2,6-dinitroaniline, m.p. 168°-169° C.

1-(3-chloro-4-trifluoromethyl-6-nitrophenyl)-2,2-dimethylhydrazine, m.p.98°-102° C.

The 3-halo derivatives are useful as intermediates for producingvaluable herbicidal 3-alkoxynitroanilines and nitro-1,3-phenylenediaminecompounds. Such compounds have the formula ##STR5## in which X ishydrogen or nitro, Y is lower alkoxy, amino, alkylamino, dialkylamino orsubstituted hydrazino of the formula ##STR6## Z is halo, especiallybromo or chloro, or trifluoromethyl, R₁ is lower alkyl, R₂ and R₃ areeach selected from hydrogen and lower alkyl, or R₁ -R₂ taken togetherrepresent alkylene, alkyleneimino or alkyleneoxy linkages having 2 toabout 6 carbon atoms in the chain. Preferably, X is nitro, Y is aminoand Z is trifluoromethyl or chloro.

The compounds are prepared by reaction of the corresponding 3-halocompound with ammonia, a primary or secondary alkylamine,alkylhydrazine, or alkali metal alkoxide according to the followingequations. ##STR7## in which X, Z, R₁, R₂, R₃ and Hal have thesignificance previously assigned, R is lower alkyl, and M is an alkalimetal such as sodium and potassium.

Reactions (a) and (b) produce the amino and alkylamino derivatives,reaction (c) produces the alkylhydrazino derivatives and (d) producesthe lower alkoxy derivatives.

In the reactions illustrated by equations (a), (b), and (c), about twomoles of the amine or hydrazine forming the N¹ group (between X and Z)can be reacted with each mole of the 3-halo substituted compound to formthe substituted 1,3-phenylenediamine compound. The reactions can takeplace in a sealed reaction vessel, such as a sealed tube or anautoclave, to avoid losses of amine and provide easy control of thereaction, or at atmospheric pressure in the presence of a solvent, suchas an alcohol, in which the amine or hydrazine is highly soluble. In thecase of higher boiling amines and hydrazines, it is not necessary to usea sealed reaction vessel for the reaction, but it is sufficient merelyto carry it out in the presence of a suitable solvent. Reactiontemperature of from about 20° to 100° C. are generally sufficient toprovide good yields of product in a reasonable period of time. Theby-product hydrogen halide is neutralized as it is formed by the excessamine or hydrazine reactant in the reaction mixture. The resultanthydrogen halide salt can be removed by filtration or washing with wateraccording to known procedures. The desired product is purified byrecrystallization or stripping under reduced pressure.

Reaction (d) takes place by combining approximately equimolar amounts ofthe reactants at a temperature of from about room temperature to about100° C. Preferably, a solvent such as the alcohol from which the metalalkoxide is derived is employed in order to control reactiontemperatures and facilitate handling of the reactants. Thealcohol-insoluble by-product metal halide is readily separated from thereaction mixture such as by filtration and the desired product isolatedand purified by conventional procedures. The desired compounds areeither high-boiling liquids or crystalline solids which can berecrystallized from a suitable solvent, such as an alcohol.

The alkali metal alkoxide is prepared by well-known procedures such asby addition of metallic sodium or potassium to the selected alcohol.

The following examples illustrate the preparation of additionalrepresentative compounds of this invention.

EXAMPLE IV N³-pentamethyleneimino-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

A 50 ml. heavy walled glass reaction tube was charged with 5.0 g. (0.01mole) ofN-pentamethyleneimino-3-chloro-2,6-dinitro-4-trifluoromethylaniline,7.59 g. (0.03 mole) of 6.06% ethanolic ammonia and about 40 ml. ofethanol. The tube was sealed and heated in an oven at 67° C. for 96hours. The tube was then opened and the contents transferred to a 500ml. flask and the reaction mixture stripped under vacuum to leave anorange-yellow residue. The residue was extracted thrice with 300 ml.portions of refluxing cyclohexane for one hour each and filtered hot,the cyclohexane insoluble solids being returned to the flask each timefor the next extraction. The cyclohexane filtrates were combined andstripped under vacuum leaving an orange-yellow solid residue. Theresidue was dissolved in 50 ml. of refluxing 95% ethanol and on coolingthe product (3.7 g.) crystallized, m.p. 132.5°-145° C. Afterrecrystallization from ethanol, the product melts at 158°-159° C.

EXAMPLE V N¹ -ethyl-N³-dimethylamino-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

To a stirred suspension of 4.0 g. (0.01 mole) ofN-dimethylamino-3-chloro-2,6-dinitro-4-trifluoromethylaniline and 100ml. of ethanol was added 1.53 g. (0.02 mole) of 70% aqueous ethylamineand about 20 ml. of ethanol. The amine solution was added dropwise overa period of about 15 minutes. The mixture was stirred at roomtemperature for 20 hours and then refluxed for 2 hours. The reactionmixture was then evaporated to dryness leaving a solid residue. To theresidue was added 200 ml. of hexane and the mixture was refluxed for onehour. The mixture was filtered hot to remove the insoluble ethylaminehydrochloride and the filtrate was transferred to a flask and evaporatedto dryness. The resultant solid residue was dissolved in 30 ml. ofrefluxing 95% ethanol, filtered hot and allowed to cool. The productcrystallized and was isolated by filtration to give 2.52 g. (61.8%),m.p. 108.5°-116° C. After recrystallization from 95% ethanol, theproduct melts at 118.5°-119.5° C.

EXAMPLE VI N³-dimethylamino-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

A 50 ml. Pyrex ampule was charged withN-dimethylamino-3-chloro-2,6-dinitro-4-trifluoromethylaniline (5.0 g.;0.015 mole), ethanolic ammonia (8.54 g. of 6.06% w/w solution; 0.03mole) and enough absolute ethanol to bring the liquid level to withinone inch of the neck. The ampule was chilled in a bath of dryice-acetone, sealed, heated with hot water (65°-75° C.) until thestarting material was in solution, and then placed in an oven at 65° C.After heating at 65° C. for 72 hours, the ampule was opened and thereaction mixture was transferred to a flask and evaporated to drynessunder vacuum. Cyclohexane (200 ml.) was added to the residue. Theresultant mixture was heated under reflux for one hour, then filteredhot and allowed to cool to 40° C., at which temperature the productbegan to crystallize. The solution was decanted away from a small amountof solids and the product was allowed to crystallize slowly from thedecantate by standing at room temperature overnight. The crystallineproduct was collected by filtration to obtain 2.7 g., m.p. 150°-153.5°C.

EXAMPLE VIIN-(dimethylamino)-2,6-dinitro-3-methoxy-4-trifluoromethylaniline

To a stirred solution of 5.0 g. (0.015 mole) ofN-(dimethylamino)-3-chloro-2,6-dinitro-4-trifluoromethylaniline and 50ml. of anhydrous methanol was added 3.77 g. (0.015 mole) of a 21.8%methanolic sodium methoxide solution. The resultant mixture was stirredat room temperature for 6 hours and was then refluxed overnight for 16hours. The methanol was then evaporated under vacuum leaving ayellow-solid residue. To the residue was added 150 ml. of water and themixture stirred for 30 minutes to dissolve the NaCl and any otherwater-soluble materials. The mixture was then filtered and thewater-insoluble solids were washed well with water. The solids were thendissolved in 30 ml. of refluxing 95% ethanol. On cooling, the productcrystallized and was isolated by filtration to give 3.83 g. (77.7%) of ayellow crystalline solid; m.p. 109°-110.5° C. After recrystallizationfrom 95% ethanol, the product melts at 110°-111.5° C.

Other compounds which can be prepared according to the above-describedprocedures include:

N¹ -methyl-N³-(dimethylamino)-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine,m.p. 145°-147° C.

N¹ -ethyl-N³-(dimethylamino)-4-nitro-6-trifluoromethyl-1,3-phenylenediamine, m.p.141°-142° C.

N¹ -methyl-N³-morpholino-4-nitro-6-trifluoromethyl-1,3-phenylenediamine, m.p.208°-210.5° C.

N¹,N¹ -dimethyl-N³-morpholino-4-nitro-6-trifluoromethyl-1,3-phenylenediamine, m.p.125°-127° C.

N¹ -ethyl-N³ -morpholino-4-nitro-6-trifluoromethyl-1,3-phenylenediamine,m.p. 158.5°-162.5° C.

N¹ -methyl-N³-piperidino-4-nitro-6-trifluoromethyl-1,3-phenylenediamine, m.p.116°-117° C.

N¹,N¹ -dimethyl-N³-piperidino-4-nitro-6-trifluoromethyl-1,3-phenylenediamine, m.p. 92°-94°C.

N¹ -methyl-N³ -methyl-N³-(dimethylamino)-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

N³ -(diethylamino)-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

N¹ -(dimethylamino)-N³ -cyclopropylmethyl-N³-ethyl-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

N¹ -ethyl-N³-(di-n-propylamino)-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

N-(diethylamino)-2,6-dinitro-3-ethoxy-4-trifluoromethylaniline

N-(dimethylamino)-3-methoxy-6-nitro-4-trifluoromethylaniline

N¹,N³ -bis(dimethylamino)-2,4-dinitro-6-bromo-1,3-phenylenediamine

N³ -(diethylamino)-2,4-dinitro-6-chloro-1,3-phenylenediamine

N¹ -cyclopropyl-N³-(diethylamino)-2,4-dinitro-6-trifluoromethyl-1,3-phenylenediamine

The compounds of this invention are herbicides and are especially usefulas selective herbicides for controlling weeds in the presence ofdesirable crops, such as cotton, soybeans and rice.

The compounds can be applied as both a pre-emergence or a post-emergencetreatment; that is, they can be applied to soil in which the weeds willgrow or they can be used to kill or suppress the growth of weeds or tokill or prevent the emergence of seedlings of undesirable plants. Thus,the compounds can be used to control the growth of weeds by applying aphytotoxic amount of one or more of the active compounds of thisinvention to the locus to be protected, that is, soil in which the weedsare growing or will grow or the foliage of the growing plants. "Weeds"as used herein is meant to include any plant growth which isundesirable.

Generally, an application rate of from about 0.5 to about 30 pounds ofone or more of the active compounds per acre is effective in controllingplant growth. Preferably, an application rate of from about 1 to about 5pounds per acre is employed. At such rates the undesirable weeds arekilled or stunted with little or no injury to desirable crops.

The following examples illustrate the herbicidal activity of typicalcompounds of this invention.

EXAMPLE VIII

The compounds to be tested were evaluated as both a pre-emergence andpost-emergence treatment. Greenhouse flats were planted to soybeans(SB), velvet leaf (VL), oats (O) and millet (M) and the flats sprayed onthe same day as planting with an ethanol-dioxane solution of thecompound to be tested at a rate of 5 pounds per acre.

Another set of flats with the same plants was treated after the plantshad emerged and were about one inch in height. These flats were alsosprayed with an ethanol-dioxane solution of the compound to be tested ata rate of 5 pounds per acre. The flats were kept in the greenhouse andwatered when needed. Seventeen to twenty-one days after treatment theflats were examined and the plants rated for herbicidal activity on a 0to 9 scale in which 0=no effect, 5=substantial injury with some kill,and 9=complete kill. The following results were obtained. (Table I)

                                      TABLE I                                     __________________________________________________________________________                      Activity                                                                      PRE        POST                                             Compound          SB VL O M  SB VL O M                                        __________________________________________________________________________    N.sup.3 --(dimethylamino)-2,4-dinitro-                                                          4  3  2 9  3  4  0 4                                        6-trifluoromethyl-1,3-phenylene-                                              diamine                                                                       N.sup.1 --methyl-N.sup.3 --(dimethylamino)-2,4-                                                 2  7  2 9  4  4  1 4                                        dinitro-6-trifluoromethyl-1,3-                                                phenylenediamine                                                              N.sup.1 --ethyl-N.sup.3 --(dimethylamino)-2,4-                                                  2  4  2 9  2  4  1 4                                        dinitro-6-trifluoromethyl-1,3-phenyl-                                         enediamine                                                                    N.sup.3 --pentamethyleneimino-2,4-                                                              0  3  5 9  0  3  5 3                                        dinitro-6-trifluoromethyl-1,3-                                                phenylenediamine                                                              N.sup.1 --ethyl-N.sup.3 --(dimethylamino)-4-                                                    0  3  3 9  2  3  2 8                                        nitro-6-trifluoromethyl-1,3-                                                  phenylenediamine                                                              N.sup.1,N.sup.1 --dimethyl-N.sup.3 --piperidino-                                                0  0  0 0  2  3  2 1                                        4-nitro-6-trifluoromethyl-1,3-                                                phenylenediamine                                                              N--(dimethylamino)-2,6-dinitro-                                                                 0  2  0 8  3  5  0 0                                        3-methoxy-4-trifluoromethyl-                                                  aniline                                                                       1-(3-chloro-4-trifluoromethyl-                                                                  0  0  0 2  2  2  1 3                                        6-nitrophenyl)-2,2-dimethylhy-                                                drazine                                                                       __________________________________________________________________________

EXAMPLE IX

N¹ -Ethyl-N³-(dimethylamino)-4-nitro-6-trifluoromethyl-1,3-phenylenediamine wasevaluated as both a pre-emergence and post-emergence treatment on abroad class of weeds and crops. Greenhouse flats were planted topigweed, cheat, wild oats, foxtail, morning-glory, water grass, rice,sugar beets, cotton, corn, barley and soybeans and the flats sprayed onthe same day as planting with an ethanol solution of the compound at arate of 2 pounds per acre.

Another set of flats with the same plants was treated after the plantshad emerged and were about one inch in height. These flats were alsosprayed with an ethanol solution of the compound at a rate of 2 poundsper acre in order to determine post-emergence activity. The flats werekept in the greenhouse and watered when needed. Twenty-one days aftertreatment, the flats were evaluated and rated as described in ExampleVIII. The following results were obtained (Table II).

                  TABLE II                                                        ______________________________________                                                        Activity                                                      Plant Specie      PRE    POSt                                                 ______________________________________                                        Figweed           8      4                                                    Cheat             2      0                                                    Wild oats         5      1                                                    Foxtail           9      4                                                    Morning-glory     3      4                                                    Rice              0      0                                                    Water grass       8      4                                                    Sugar beets       4      3                                                    Cotton            0      2                                                    Corn              3      0                                                    Barley            0      0                                                    Soybeans          0      0                                                    ______________________________________                                    

Since a relatively small amount of one or more of the active compoundsshould be uniformly distributed over the area to be treated, they arepreferably formulated with conventional herbicide carriers, eitherliquid or solid. Thus, the compounds can be impregnated on or admixedwith a pulverulent solid carrier such as lime, talc, clay, Bentonite,calcium chloride, vermiculite, calcium carbonate, and the like.Alternatively, the compounds can be dissolved or suspended in a liquidcarrier such as water, kerosene, alcohols, diesel oil, xylene, benzene,glycols, ketones, and the like. A surfactant is preferably included toaid dispersion, emulsification and coverage. The surfactant can be ionicor non-ionic, and may be a liquid or a solid. The use of the term"surfactant" herein is intended to include such compounds commonlyreferred to as wetting agents, dispersing agents and emulsifying agents.Typical surfactants include the alkylarylsulfonates, the fatty alcoholsulfates, sodium salt of naphthalenesulfonic acid, alkylaryl polyetheralcohols, long chain quaternary ammonium compounds, sodium salts ofpetroleum-derived alkylsulfonic acids, polyoxyethylene-sorbitanmonolaurate, and the like. These dispersing and wetting agents are soldunder numerous trademarks and may either be pure compounds, mixtures ofcompounds of the same general group, or they can be mixtures ofcompounds of different classes. Surfactants can also be included incompositions containing a solid inert carrier.

Concentrated compositions containing the active agent which can besubsequently diluted, as with water, to the desired concentration forapplication to plants and soil are also provided. The advantages of suchconcentrates are that they are prepared by the manufacturer in a formsuch that the user need only mix them with a locally available carrier,preferably water, thereby keeping shipping costs to a minimum whileproviding a product which can be used with a minimum of equipment andeffort. Such concentrates may contain from about 5 to about 99 percentby weight of one or more of the active compounds with a carrier ordiluent, which may be a liquid or a solid. Liquid carriers which aremiscible with the active agent or other liquids in which the compoundmay be suspended or dispersed can be used. A surfactant is alsogenerally included to facilitate such dilution or dispersion in water.However, the surfactant itself may comprise the carrier in suchconcentrates.

The herbicidal compositions can include other beneficial adjuvants, suchas humectants, oils and contact agents. Also, other herbicides such asthe sodium borates, sodium chlorate, chlorophenoxyacetic acids,substituted uracils and ureas, triazines, benzimidazoles, carbamates,anilides, amides, and haloalkanoic acids, can be included in theformulation.

Various changes and modifications of the invention can be made and, tothe extent that such variations incorporate the spirit of thisinvention, they are intended to be included within the scope of theappended claims.

What is claimed is:
 1. A compound of the formula ##STR8## wherein X isselected from hydrogen and nitro, Y is halo, Z is selected from halo andtrifluoromethyl, R₁ is lower alkyl, and R₂ and R₃ are each selected fromhydrogen and lower alkyl.
 2. A compound in accordance with claim 1 inwhich Y is bromo or chloro.
 3. A compound in accordance with claim 1 inwhich X is hydrogen, and Z is trifluoromethyl.
 4. A compound inaccordance with claim 2 in which X is nitro and Z is trifluoromethyl. 5.The compound in accordance with claim 1,N-(methylamino)-3-chloro-2,6-dinitro-4-trifluoromethylaniline.
 6. Thecompound in accordance with claim 1,1,1-dimethyl-2-(3,4-dichloro-6-nitrophenyl)hydrazine.
 7. The compound inaccordance with claim 1,N-(dimethylamino)-3-chloro-2,6-dinitro-4-trifluoromethylaniline.
 8. Thecompound in accordance with claim 1,N-(dimethylamino)-3,4-dibromo-2,6-dinitroaniline.
 9. The compound inaccordance with claim 1,1-(3-chloro-4-trifluoromethyl-6-nitrophenyl)-2,2-dimethylhydrazine.